So after some planning and debate, I decided to tackle this mod. It's a work in progress. The host is one of those pistol grip 1 million candlepower spot lights. It had a 55W H3 automotive halogen lamp running on 6V off a sealed lead acid battery. I realized the reflector wouldn't work with an led after cutting it down to get it to focus so I improvised and stuck a reflector in the reflector!
For power, I'm using a 3S2P battery with Samsung 25R's. I couldn't use old laptop batteries since it's higher current. I had to cobble together the battery to get it to fit in the host...its a prototype so not the final version which will have flat conductors connecting the series and parallel cells.
The emitter is a 5000k xhp 70.2 6V.
The wires pass through the heatsink. They're like that for testing.
The driver is a China special 5-mode 5A buck driver.
Since my host is plastic and not compatible with this driver (I bought it for a different project I scrapped), I had to make it work. I built a heatsink/ holder out of some laptop heatsink cooling pads, soldered and drilled out to hold the driver. I mounted it to the heatsink where the whole assembly will be fan cooled. Yes it works, but there are some kinks to sort out.
That's it for now. I'm waiting for another driver from China because I've killed two so far, but will work on the reflector more later. Hope you like this, and stay tuned for more!
Curious, what was the problem you had with the reflector that made it not workable? I started a mod on a “10 million candlepower” light some years ago, and the reflector worked fine with MT-G2. I did have to move the MT-G2 up into the focal point by making an Aluminum pedestal for the MCPCB to sit on. But I accidentally stripped the shiny coating off the reflector and finally couldn’t use it for that reason. I stopped working on it after that, and ended up giving the MT-G2 away after a while. I had about as good a focus as could be expected from any incan reflector. It was definitely better than the cheap halogen bulb that was there before.
That was the issue I ran into. I would have loved to see how you did that and made it work. And yes, unless you get into the hundreds of watts, a single led will make more light than an incandescent light source and a lot less heat per lumen.
Logistically it was possible, but I wanted to try the other way for yucks. I knew I would have had to move the emitter up into the reflector to compensate for the roughly 120-125 degree view angle from the led versus the 360 degree light dispersion pattern from an incandescent bulb. I didn’t want to mess with fabricating a pedestal to put the emitter on, drill holes in it for the leads, etc. and potentially damage the reflector. Plus I run my LEDs hot so I got better thermal management the other way. I hope this works!
I have a short piece of 25mm round Aluminum bar that I got from Dale (DB Custom) a while back and have used pieces of it for a couple of projects. This was one of those. I cut off a piece about an inch long and lapped one end flat/smooth for the MCPCB, and made the other end fit in the old bulb opening in the reflector.
The way I ruined my reflector was trying to polish it. I didn’t know it was a coating, and underneath was a clear (epoxy?) coating to make it smooth, then under that just junk metal. If I wanted to, I could sand away the clear coat and try to polish the metal, but it won’t do much good, and salvaging the light just isn’t worth all that work to me now for subpar results.
They are all made pretty much the same way, stamped and spot welded sheet steel that’s coated with chrome then has an epoxy on the inside and outside for corrosion resistance. I found that out when I was grinding it on my belt sander…funky smells! I’d have liked to seen what the post thing looked like with photos of the beam pattern.
So here's some tinkering I did today. Preparing to mount the base of the reflector to the heat sink assembly. I'm planning on fabricating a mount for the reflector as well. I'm trying to keep it modular for easy disassembly.
The aluminum ring is about 4mm tall and 35mm wide. It's a spacer that goes between the platters of a hard disk drive. Here it's a spacer/ mount for the bottom of the reflector. It sits on top of the heat sink.
I could have spent a couple hours drilling holes into it and mounting it with screws, but why when you have JB Weld? I put thermal paste between the ring and heatsink since the reflector base will be aluminum and I will get some residual heatsinking. Yes, the bottom of the reflector is the top cover from a hard drive.
Update! Here's the first images of the beam patterning. This is the most tedious part of the mods I do. It took 4 hours of grinding, sanding, and filing to get this far, but I'm pretty much done. I wasn't going for crazy throw or flood, but a nice mix. I think I got it.
It's insanely bright. The pictures don't do it justice. It's on my ceiling at about 7 feet. Next up is mounting the reflector, finishing the base, painting it, and attaching the whole assembly together to the heatsink and fan.
In the mean time, I cut the opening for the balance connector.
The charging plug is next to the balance connector port.
Here's some of the latest work I've done, mostly fails, but some progress. I started working more of the base of the reflector where the LED sits, and decided on using threaded standoffs like you use in computer motherboards to mount them to the case. I drilled 8, 3mm holes in the plate for mounting the standoffs.
I was planning on threading the threaded ends in between the heatsink vanes, but that would have been too difficult so I scrapped that idea. I found some bigger separators with threaded inserts.
They were a little tall and wide, but nothing some belt sanding couldn't fix. I lmost got them to work, but I lost one after it spun off the threaded rod I was using to hold it while reducing the outer diameter and height on my belt grinder. Boo. Now it's off the hardware store to see if I can find something different. Any ideas?
In the meantime, I mounted the fan mounts to the heatsink assembly with JB Weld. The ends are threaded to accept self -tapping screws.
Once that's dry and I find a way to mount the reflector base, I'll mount the reflector to the base. I'm planning on keeping everything one single unit that breaks down into 2 or 3 parts for maintenance.